Automatic two-way brake for hoists



March 12, 1935. s MORISQN ,9

AUTOMATIC TWO-WAY BRAKE FOR HOIS'IS V Filed June 2, 1934 2 Shets-Sheet 1 WITNESSES v INVENTOR v March 12, 1935. G. s. MORISON AUTOMATIC TWO-WAY BRAKE FOR HOISTS 2 sneets sheet 2 Filed June 2, 1954 Patented Mar. 12, 1935 UNITED ST TES AUTOMATIC Two-WAY BRAKEFOR HOISTS George Smith Morison, Pittsburgh, Pa., assignor to Morison Incorporated, Pittsburgh, Pa., a corporation of Delaware Application June 2, 1934',- Serial No. 728,725

12 Claims. (01. 254-169) raised and lowered by a load-chain which is actuated by means of a hand-chain operably connected thereto through suitable gearing. In hoists known heretofore one end of the load-chain is hooked up in inoperative position, theopposite end being used for doing all of the work of raising and lowering loads. This is because the automatic braking mechanism, which prevents the load from falling whenever the hand-chain is released, is capable of functioning when the load is onv one predetermined end of the load-chain only.

Consequently, in carrying successive loads in the same direction the hoist does no-work while the load end of the chain is returning empty to the starting point to pick up the next succeeding load. This means that the ordinary type of hoist is incapable of doing work during half of the period it is in operation and that wear of moving parts is unevenlydistributed in the'hoist, a waste which it is desirable to avoid.

It is among the objects of this invention to provide a chain hoist or the like which operates successfully with loads carried by either end of its load-chain.

A more specific object is to provide such apparatus with automatic braking mechanism adapted to function. properly regardless of which end of the load-chain is carrying a load.

7 Further objects are to provide braking mechanism for the above purpose which is strong, durable, instantly responsive, easy to assemble and disassemble, and simple 'in construction.

The preferred embodiment of the invention is illustrated in the accompanying drawings, of which Fig. 1 is a side view of a hoist partly broken away to show the braking mechanism and related parts; Fig. 2 a vertical section taken on the line II-.-II of Fig. 1 and showing the load-chain diagrammatically; Fig.3 a view similar to Fig. 2 with one set of brake shoes applied; and Fig. 4 a viewof a modified detail.

Referring to Fig. 1 of the drawings, a housing is provided consisting of two substantially cylindricalhousing shells 1 and 2, held in spaced. relation and axial alignment by a series of spacing bolts 4 which connect the inner walls 6 and 7 of the housing shells. Between the upper portions of the housing shells 1 and 2 there is disposed the lower end of a hoist-supporting swivel hook 8 having laterally projecting trunnions 9 piv otally mounted in reinforcing hanger plates 10 The centers and extending into bores in inner end walls 6 and "7. p of the inner walls G and '7 are provided with openings in which are disposed bearings 11 having a hollow shaft 12 journalled therein. A load-chain-wheel 13 is splined on this shaft in the space between theinner end walls, and is provided with the usual grooves and recesses in its periphery for receiving the linksof a load-chain 14 so that the'chain will move as the wheel 13 rotates. This hollow shaftf12 has interior bearings 16 fitted in its bore in which a. driving shaft 17, extending from end to end of the housing, is journalled. The driving shaft 17 is operably connected to the load-chain shaft 12" by means of suitable gearing, not shown, disposed in housing shell 2. As shown diagrammatically in Figs. 2 and 3, both ends of load-chain 14 are provided with load-carrying hooks 18, the use of both or either of which is made possible by novel braking means disposed .in housing shell 1 and about to be described. 7

In accordance with this invention a brake drum, consisting of a circular housing end plate 20 having an integral peripheral braking flange 21, is screwed into the open outer end of housing shell 1 where it is locked by means of a set screw 22' projecting through a threaded bore in the circular wall of the housing and into a hole in the peripheral face of the end plate. Keyed on the adjacent'end oi the driving shaft 17 is a hub 23 preferably extending from end plate 20 to a point adjacent inner end wall 6. Loosely mounted on the outer end of this hub is a lever-carrying momher or braking disc 2% provided at diametrically opposite points near its periphery with threaded transverse bores 25 from e'ach'of which a pin 26 extends inward toward the center of thehousing. Loosely mounted on the exposed portion of each, of these pins is a segmentelike lever- 27 adapted to be rocked thereointhe pin-receiving o'pening'ZS of the lever being near its outer edge midway between its ends.

Each segment-like lever 27 carries a pair of brake shoes 29 and 30 for frictional engagement with the braking surface 31 of the braking flange 21, one shoe being disposed on each side of pin 26. Eachbrakeshoe'isconnected to its carrying lever 27 by an integral'radial lug 32 having an enlargedrounded end rockable in a registering recess 33 of the same general shape as the lug, the recess being formed in the outer portion of the lever. The lug 32 is long, enough to space the shoe a-short distance from the lever 2'7 so that the shoe. can rock relative thereto for bringing its entire outer surface into frictional engagement with the brake drum face 31 when the lever is rocked in that direction. The brake shoes are prevented from moving laterally by an annular shoulder 34 in the braking flange 21 and an outwardly extending radial flange 36 on the outer edge of the levers 27, while the cooperating lugs 32 and recesses 33 otherwise lock the shoes and levers together.

Midway between the ends of each lever 27 it is provided with an integral radial arm 37 which projects into a shallow recess 38 in a collar 39 integral with hub 23. When the outer ends of a lever 27 are spaced equal distances from the axis of the braking disc 24 as shown in Fig. 2, that is, when the lever is centered, both brake shoes 29 and 30 carried thereby are held out of contact with the brake drum.

If a weight on either end of the load-chain starts to turn the load-chain-wheel and, through it, shafts l2 and 17, hub 23 keyed on shaft 17 is also turned, whereupon hub collar 39 swings arms 37 in one direction or the other, depending on which way the load-chain attempts to move. A very slight movement of arms 37 in either direction from their central positions is sufficient to cause each lever 27 to force a brake shoe into frictional engagement with the face 31 of the fixed brake drum, thereby immediately checking the fall of the load on the load-chain. This operation of the brake mechanism is illustrated in Fig. 3 where diametrically opposite brake shoes 29 have been applied to the brake drum by the downward pull of one end of the load-chain which has turned hub 23 and its collar in a counterclockwise direction.

In order to operate the hoist to raise and lower loads, an endless hand-chain 42 is provided which is carried by a hand-chain-wheel 43 in the same way as the load-chain is carried by the loadchain-wheel. The hand-chain-wheel is loosely mounted on the inner end of hub 23 between its collar 39 and inner end wall 6, and the hand-chain passes in and out of housing shell 1 through a slot 45 therein. The outer face of this wheel 43 is provided with a pair of diametrically opposed integral bosses 44 which project into arcuate recesses 46 formed in the hub collar 39 at right angles to the shallow recesses 33 therein.

These arcuate recesses are of such length tha when the ends of the levers 27 are spaced equal distances from the axis of the braking disc 24, as shown in Fig. 2, the outer and inner side faces of each boss 44 can simultaneously engage, respectively, one end of either lever 27 and the adjacent end wall of an arcuate recess 46. When the bosses 44 are forced simultaneously against the levers 27 and the end wall of the arcuate recesses 46 in hub collar 39 by a force exerted on the handchain, the hand-chain-wheel 43, levers 27, brake disc 24, hub 23, collar 39 and driving shaft 17 are made to rotate as a unit around the axis of the driving shaft because the contacting ends of the levers 2'7 and bosses 44 are so shaped as to cause the levers to be pushed along by the bosses while at the same time preventing those ends of the levers from being rocked toward hub 23, thereby preventing the brake shoes from being applied which would halt all movement. As shown in Figs. 2 and 3, the contacting ends of the levers and bosses may be tapered for this purpose. Rotation of hub collar 39 is transmitted through hub 23, driving shaft 17, the gearing, and hollow shaft 12 to the load-chain-wheel 13, whereby the loadchain 14 is actuated.

Whenever the hand-chain is released the bosses 44 will no longer exert pressure against hub collar 39 and the levers 27, whereupon a load on the load-chain tends to drop, but in so doing it starts to rotate the load-chain-wheel 13 which, through the gearing, rotates shaft 17 and hub 23 with its collar 39. As bosses 44 do not now restrict movement of levers 2'7 and hub collar 39, the latter is free to turn and the levers, through their arms 37, are free to be rocked by it. The slightest movement of the hub collar in either direction, caused by the weight of the load, swings radial arms 37 of the levers in the same general direction, thereby rocking the levers and applying a pair of diametrically opposite brake shoes. The hub 23 can then no longer rotate because its collar bears against the immovable radial arms 37 of the then stationary levers. All of this happens practically instantaneously without perceptible fall of the load. The applied brake shoes always being at diametrically opposite points, the braking pressure is not applied in a lopsided manner permitting probable slippage and causing undue strain and wear on the mechanism.

By way of more graphic illustration of the operation of the hoist, let it be assumed that in Fig. 3 a load is suspended from one of the load hooks 13, and that the weight of the load has turned the hub collar 39 in a counterclockwise direction which in turn swung radial arms 3'7 and rocker levers 2'7 until diametrically opposed brake shoes 29 were forced tightly against the face 31 of the brake flange, thereby preventing the load from falling. To raise the load from its suspended position the hand-chain is pulled to rotate the hand-chain-wheel 43 and its bosses 44 in a clockwise direction as viewed in Fig. 3. However, the bosses can not move without turning the hub collar 39 with them, and the moving collar swings lever arms 37 with it until diametrically opposite ends of the levers strike against the bosses, as shown in Fig. 2, whereby all relative movement between levers, bosses and collar ceases. Thereupon, the brakes having been released by this movement of levers 2'7, all of the braking mechanism, the bosses, hub and driving shaft rotate as a unit in the same direction as the hand-chainwheel. If the load were on the other load hook the movement of all parts of the hoist would be in the direction opposite from that just described. On the other hand, if the load on the lastmentioned hook in Fig. 2 were being lowered, the positions of the moving parts would still be as there shown, and their movement would be in a clockwise direction. However, when the pull on the hand-chain ceases, hub collar 39 is permitted to turn relative to levers 27 because bosses 44 no longer offer any resistance to inward movement of the contacting ends of the levers toward hub 23. As the lever arms are then free to be swung by the hub collar, the levers are rocked on their pivot pins 26 until brake shoes 30 engage face 31 of the brake flange and stop further movement of the component parts or" the hoist. When it is desired to further lower the load the hand-chain is again pulled in a clockwise direction, which forces the tapered ends of bosses 44 against the in-swung ends of the levers which are thereby forced outward. This movement centers the levers and simultaneously withdraws brake shoes 33 from the brake flange so that the driving shaft 17 can again rotate.

This automatic two-way brake virtually doubles the capacity and eiliciency of hoists now in use, because when one load-carrying hook is in raised position the otherhook, is in lowered position, The use of both ends of the load-ohainresults in the hoist meohanism being operated about an equal amount inv both directions, thereby distributing wear uniformly throughout the mechanism. The braking mechanism is immediately and unfailingly responsive to the slightest tendency of a load to drop. The entire area of the brake shoes braking surfaces is forced into engagement with the brake drum' so quickly and positively that there is no perceptible drop in the load, and the wear on the shoesis very slight.

Although the brake shoes of this two-way braking mechanism are interchangeable and. easily removable when worn, the mechanism can be constructed in such a way that it will function properly until the brake shoes are substantially worn through. By reference to Fig. 3 it will be seen that as brake shoes 29 are worn down, hub collar 39 will swing radial arms 37 a substantial distance in a counterclockwise direction in ap-v plying those shoes to brake flange 21. However, when the hub collar attempts to return to its original position, its movement may be restrained by the ends of radial arms 3'1 disposed in its path.

To prevent such an occurrence the modification of hub collar 39 and radial arms 37 shown in Fig. 4 is suggested.

As there shown, each recess 38 in the hub coliar is provided with a radialtooth 51 which projects into a recess 52 in the end of an adjacent radial arm 37, whereby a small segment of a gear is formed at the juncture of the collar with each radial arm. With this construction, it is possible to return radial arms 37 from positions at a substantial distance from their central positions, because teeth 51 engage the walls of recesses 52 and swing the armsback so that the hub collar can not jam against the ends of the arms.

As will be observed in the drawings, the construction and assembly of this hoist is relatively simple. Aside from the spacing bolts which hold the two housing shells together, and the two screws which look the end plates in place, there are nobolts and nuts or screws in the structure. By loosening screw 22 end plate 20 can be turned out of housing shell 1 by the hand. This gives unrestricted access to the braking mechanism which can he slipped off the-end of the driving shaft as a unit. When braking disc 24 is removed with rocker levers 27, the latter can he slipped off the ends of pivot pins 26, and the brake shoes slipped sideways out of recesses 33. With the removal of hub 23 comes the handchain-wheei which is loosely mounted thereon. When the braking machinsm is assembled the hub of the hand-chain-wheel prevents the levers from working off their pivot pins 26'by obstructing the movement of radial arms 37 in that direction.

desired, braking flange 21 can-be omitted from end plate 20 and the braking mechanism enlarged so that the brake shoes can directly engage the inner surfaceof housing shell 1. On the other hand, the braking flange can be'omitted from end plate 20 and the positions of the braking mechanism. and hand-chain-w'heel transposed so that the brake shoes can engage a braking flange formed on inner endwall 6.01 the housing. 1

According to the provisions of the Patent Statutes, I have explained the principle and mode of operation of my invention, and have. illustrated and described what I now consider to be.its. best applied tethe drum, means for transmitting.

turning movement of the driving. shaft in either direction to the braking means for applying the brake, said turning movement being caused by weight of a load on the load-chain, a handchain-wh el journalled in the housing'ahandchain for turning the hand-'chain-wheel, and means connected to said wheel for holding the braking means out of engagement with the brake drum when the hand chain-wheel is being turned, said connecting means also being oper ably connected to the driving shaft for rotating it with the hand-chain-wheel.

2. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to s'upportloads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, lever means, 1 means for transmitting turning movement of the driving shaft in either direction to the lever means for actuation thereor", said turning movement being caused by weight of a load on the load-chain, braking means adapted to be moved into-frictional engagement with the brake drum by said actuated lever means, a 'hand-chain-wheel journalled in the housing, a hand-chain for turning the handohain-wheel, and means connected. to said wheel for rotating the driving shaft and for holding he lever means against actuation while the hand-chain-wheel is being turned.

3. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, lever-carrying means disposed in the housing, rockable lever means carried by the lever-carrying means, means rigidly associated with the driving shaft'for rocking the lever means in either direction in accordance with the turning of the load-chain-wheel by the pull of a load on the load-chain, braking means adapted to be moved into frictional engagement with the brake drum by the lever means, a hand-chainwheel journalled in the housing, a hand-chain for turning the hand-chain-w'heel, and means connected to said wheel for rotating the driving shaft. and for holding the lever means against rocking while the hand-chain-wheelv is being turned in either direction.

4. A hoist comprising a housing, a load-chainwheel journalled therein, a'load-chain suspended from the wheel and adapted'to support loads from either of its depending ends, a driving shaft, gearing operably connectingthe driving shaft with theload-chain-wheel, a brake drum in the housing, a lever-carrying member disposed in the housing, a plurality of rocizable. levers pivotally mountedonsaid membena brake shoe carriedby each lever for engaging the brake drum, the brake shoes being out of contact with the brake drum when the levers are centered, means rigidly connected to the driving shaft for rocking the levers in either direction in accordance with the turning of the load-chain-wheel by the weight of a load on the load-chain, a hand-chain-wheel loosely mounted on the driving shaft, an endless hand-chain for turning the hand-chain-wheel, and means projecting laterally from the handohain-wheel and adapted to engage the leverrocking means for rotating the load-chain-wheel, said projecting means cooperating with the leverrocking means in centering the rockable levers when the hand-chain-wheel is turned in either direction.

5. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, a lever-carrying member disposed in the housing, a plurality of rockable levers pivotally mounted on said member, a brake shoe carried by each lever for engaging the brake drum, the brake shoes being out of contact with the brake drum when the levers are centered, a collar rigidly connected to the driving shaft adjacent the levercarrying member and provided with a plurality of recesses in its periphery, an arm projecting from each of the levers substantially midway of its length into one of the recesses whereby movement of the collar caused by the turning of the ioad-chain-wheel in either direction swings said arms and rocks the levers to apply the brake shoes to the brake drum, a hand-chain-wheel loosely mounted on the driving shaft, an endless hand-chain for turning the hand-chain-wheel, and means adapted to connect the hand-chainwheel to the collar for rotating the load-chainwheel, said connecting means cooperating with the collar in centering the rockable levers when the hand-chain is pulled in either direction.

6. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, a lever-carrying member disposed in the housing, a plurality of rockable levers pivot lly mounted on said member, a brake shoe carried by each lever for engaging the brake drum, the brake shoes being out of contact with the brake drum when the levers are centered, a collar rigidly connected to the driving shaft adjacent the levercarrying member and provided with a plurality of recesses in its periphery, an arm projecting from each of the levers substantially midway of its length into one of the recesses whereby move- 1 merit of the collar caused by the turning of the load-chain-wheel in either direction swings said arms and rocks the levers to apply the brake shoes to the brake drum, a hand-ohain-wheel loosely mounted on the driving shaft, anrendiess hand-chain for turning the hand-chain-wheel, and a plurality of bosses projecting laterally from the hand-chain-wheel and adapted to engage the collar for rotating the load-chain-wheel, said bosses cooperating with the collar in centering the rockable levers when the hand-chain is pulled in either direction.

7. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, a lever-carrying member disposed in the housing, a rockable lever pivotally mounted on said member, a brake shoe carried by the lever on each side of its pivot axis for engaging the brake drum when said lever is rocked, said shoes being out of contact with the brake drum when the lever is centered, means rigidly associated with the driving shaft for rocking the lever in either direction in accordance with the turning of the load-chain-wheel to apply one of the brake shoes to the brake drum, a hand-chain-wheel journalled in the housing, a hand-chain for turning the hand-chain-wheel, and means operably connecting the hand-chain-wheel to the driving shaft for rotating the load-chain-wheel, said connecting means cooperating with the leverrocking means in centering the rockable lever when the hand-chain-wheel is turned in either direction.

8. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum rigidly disposed in the housing, a lever-carrying member loosely mounted on one end of the driving shaft, a rockable lever pivotally mounted on said member, a brake shoe carried by the lever on each side of its pivot axis for engaging the brake drum when said lever is rocked, said shoes being out of contact with the brake drum when the lever is centered, means rigidly connected to the driving shaft for rocking the lever in either direction in accordance with the turning of the load-chain-wheel to apply one of the brake shoes to the brake drum, a hand-chainwheel journalled in the housing, a hand-chain for turning the hand-chain-wheel, and means connecting the hand-chain-wheel to the leverrocking means for rotating the load-chain-wheel, said connecting means cooperating with the lever-rocking means in centering the lever when the hand-chain-wheel is turned in either direction.

9. A hoist comprising a housing, a load-chainwheel journalled therein, a load chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum rigidly disposed in the housing, a lever-carrying member loosely mounted on one end of the driving shaft, a plurality of rockable levers pivotally mounted on said member, a brake shoe carried by each lever on each side of its pivot axis for engaging the brake drum when the levers are rocked, said shoes being out of contact with the brake drum when the levers are centered, means rigidly connected to said shaft for rocking the levers in either direction in accordance with the turning of the load-chain-wheel to apply the brake shoes to the brake drum, a hand-chainwheel loosely mounted on the driving shaft, an endless hand-chain for turning the hand-chain wheel, andmeans projecting laterally from the hand-chain-wheei and adapted to engage the lever-rocking means for rotating the load-chainwheel, said projecting means cooperating with the lever-rocking means in centering the rockable levers when the hand-'chain-wheel is turned in either direction.

10. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaftwith the load-chain-wheel, a brake drum rigidly disposed in the housing, a lever-carrying member loosely mounted on one end of the driving shaft, a plurality of rockable levers pivotally mounted on said member, a brake shoe carried by each lever on each side of its pivot axis for engaging the brake drum when the levers are rocked, said shoes being out of contact with the brake drum when the levers are centered, a collar rigidly connected to the driving shaft adjacent the levercarrying member and provided with a plurality of recesses in its periphery, an arm projecting from each of the levers substantially midway of its length into one of the recesses whereby movement of the collar caused by the turning of the load-chain-wheel in either direction swings the arms and rocks the levers to apply one-half of the number of brake shoes tothe brake drum, a hand-chain-wheel loosely mounted on said shaft, an endless hand-chain for turning the hand-chain-wheel, and means adapted to connect the hand-chain-wheel to the collar for rotating the load-chain-wheel, said connecting means cooperating with the collar in centering the rockable levers when the hand-chain is pulled in either direction.

11. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum rigidly disposed in the housing, a lever-carrying member loosely mounted on one end of the driving shaft, a plurality of rockable levers pivotally mounted on said member, a brake shoe carried by each lever on each side of its pivot axis for engaging the brake drum when the levers are rocked, said shoes being out of contact with the brake drum when the levers are centered, a collar rigidly connected to the driving shaft adjacent the lever-carrying member and provided with a plurality of recesses in its periphery, an arm projecting from each of the levers substantially midway of its length into one of the recesses whereby movement of the collar caused by the turning of the load-chain-wheel in either direction swings the arms and rock the levers to apply one-half of the number of brake shoes to the brake drum, 2. hand-chain-wheel loosely mounted on said shaft, an endless hand-chain for turning the hand-chain-wheel, and a plurality of bosses projecting laterally from the hand-chain-wheel and adapted to engage the collar for rotating the driving shaft and load-chain-wheel, said bosses cooperating with the collar in centering the rockable levers when the hand-chain is pulled in either direction.

12. A hoist comprising a housing, a load-chainwheel journalled therein, a load-chain suspended from the wheel and adapted to support loads from either of its depending ends, a driving shaft, gearing operably connecting the driving shaft with the load-chain-wheel, a brake drum in the housing, a lever-carrying member disposed in the housing, a plurality of rockable levers pivotally mounted on said member, a brake'shoe carried by each lever for engaging the brake drum, the brake shoes being out of contact with the brake drum when the levers are centered, a collar rigidly connected to the driving shaft adjacent the lever-carrying member and provided with a plurality of recesses in its periphery, an arm projecting from each of the levers substantially midway of its length into one of the recesses whereby movement of the collar caused by the turning of the load-chain-wheel in either direction swings said arms and rocks the levers to apply the brake shoes to the brake drum, each of said arms being provided in its end with a radial recess, a tooth projecting radially from,

the collar at the center of each of said collar recesses and into the adjacent arm recess whereby a gear tooth connection is formed between the collar and said arms, a hand-chain-wheel loosely mounted on the driving shaft, an endless handchain for turning the hand-chain-wheel and means adapted to connect the hand-chain-wheel to the collar for rotating the load-chain-wheel, said connecting means cooperating with the collar in centering the rockable levers when the hand-chain is pulled in either direction.-

GEORGE SMITH MORISON. 

